Deformational plagiocephaly occurs most often in infants of four months age or younger because (i) the skulls of young infants are still easily deformed; (ii) the calvaria are rapidly expanding against a flat surface; (iii) non-fixed cranial sutures make the skull more malleable, and iv) such infants are neuromuscularly immature and lack the coordination to shift their head position. If left uncorrected and the pressure remains continuously or repeatedly applied, the existing deformation will likely become permanent.
There are adaptable orthotic devices that can correct and/or prevent deformational plagiocephaly, especially if used before the infant is 4 months of age. For example, U.S. Pat. Nos. 7,810,501 and 8,186,354 describe embodiments utilizing a plurality of removable stacked layers that are taken out as the size of the baby increases (in the manner of layers of an onion). However, such devices are not ideal for very small babies.